Fasteners such as snap fasteners, buckles and snap fasteners are commonly used for fastening elements to one another. Snap fasteners are often used for preventing theft of items from shops and typically include a set of spherical elements removably snapping a metallic elongated protrusion of the fastener such that the snap holding can only be released by using a powerful magnet externally from the fastener to pull out the metallic protrusion attracted to the magnet. These fasteners are typically equipped with RFID (radio frequency ID) tags to have a detector detect them to prevent shoplifting for instance, when used for attaching to articles in a shop.
US patent application publication No. 2005186027 teaches a fastener having a key to fasten two separate articles for backpacks or bags carrying personal belongings or valuables or the like, and the fastener includes the fastener includes at least two locking pins installed in the receiving unit and resiliently supported by a biasing member, a key receiving groove formed on a front surface of the receiving unit in a desired depth and having an optional shape, a plurality of locking holes, formed in the inserting unit at a position corresponding to the locking pin, for receiving the locking pin, so that the inserting unit is snapped to the receiving unit, and a key adapted to complementarily match with the key receiving groove formed on the front surface of the receiving unit, and having a permanent magnet displaced at a position corresponding to the locking pin to pull the locking pin from the locking hole. When the inserting unit is inserted into the receiving unit, the locking pin installed in the receiving unit and biased therein by a biasing member is snapped to the locking hole of the inserting unit. A fastening state of the inserting unit is released by inserting the key into the key receiving groove formed on the front surface of the receiving unit.
US patent application publication No. 2003145441 teaches a fastening mechanism comprising a pin having a shank coupled to the head at a first end of said shank. A metallic pin-lock is provided having a base portion coupled to a resilient pin-engaging portion. The shank has a circumferentially-formed notch at a second end, said notch being adapted to receive the resilient pin-engaging portion. A resilient member is coupled to the base portion of the metallic pin-lock and to a mobile phone housing. A retainer is provided for housing said fastening mechanism inside the mobile phone housing. Upon insertion of the pin into the pin-lock, the pin is adapted to move the resilient pin-engaging portion a predetermined distance until the resilient pin-engaging portion engages the circumferentially-formed notch. The pin-lock is adapted to be removed from the pin via a magnet attracting at least a portion of the pin-lock away from the pin.
Other references such as WO2013086562, EP1947973, U.S. Pat. No. 7,535,356, US2007120686, WO02060293, DE202005001787 and US2004092874 also disclose various types of magnet or buckle type fasteners.